1. Field of the Invention
The present disclosure relates to a minimally invasive method of fat cavitation.
2. Description of the Background of the Technology
Cosmetic surgery, which is mainly consumer driven, represents one of the fastest growing areas in medicine. As people age, they, along with their children, spend millions of dollars each year on cosmetic and aesthetic improvements. Liposuction is one of the most frequently requested of these cosmetic procedures. The American Society of Plastic Surgeons (ASPS) reports that there were over 400 thousand liposuction procedures performed in 2001, making it one of the five most frequently performed cosmetic procedures in the United States. According to the ASPS 2000 national statistics, the total number of liposuction procedures performed in the United States was 354,015. There is a strong rate of growth in the number of procedures performed every year. Recently, there is an increase in the number of microliposuction procedures.
More than 50% of the population of the United States is overweight or obese—this fact is well established. For this segment of the population, plastic and cosmetic surgeries play a complementary role to weight loss training and personal training in improving their quality of life.
The target of liposuction, adipose tissue, is found in the innermost layer of the skin, the subcutaneous layer. The outermost layer of the skin is known as the epidermis, while the intermediate layer is known as the dermis. Fat lysis is a procedure which results in the permanent reduction of adipose tissue. The most commonly accepted liposuction technique utilizes a cannula with a blunt closed tip rather than an open tip or a pointed or sharpened tip. This cannula is a metal tube, about the size of a pencil, which is attached to a suction pump. The cannula, with its rounded tip, is sometimes passed through the fat first, without suction, to develop the proper passageways. Then suction is applied and the surgeon continues passing the cannula through the fat tunnels with repeated radial thrusts and on several levels of the tissue. Adipose tissue is aspirated through a hole in the side of the cannula near its distal end. The cannula must be moved back and forth several times through each tunnel. Problems associated with this technique are similar to those experienced with the older methods of liposuction. Even with a blunt edge at the distal end of the cannula, fat globules are torn off by both scraping and suction power at the side hole. The bleeding is also similar in amount to that resulting from the use of the older, sharp-edged instruments which cut fat tissue and blood vessels without suction.
An alternative technique involves the addition of high frequency ultrasound to traditional liposuction. This procedure typically employs titanium cannulas through which ultrasonic waves are passed. The ultrasonic waves result in disruption of the adipose tissue, making suction of the emulsified adipose tissue through the cannula a somewhat easier process. Another variant includes the use of external ultrasound on the skin overlying the adipose tissue followed by traditional liposuction. With this external application of ultrasound, the adipose tissue is probably dispersed in the tumescent medium prior to being removed through suction.
The safety and efficacy of liposuction have improved over the last twenty years since the treatment began in the United States. Nevertheless, it still has many disadvantages. Complications from liposuction arise from damaged blood vessels. As a result, organized semi-solid blood clots known as “hematoma” form causing damage to overlying skin, as well as contour irregularities. Other complications, such as seroma formation (the collection of body fluids) can produce infection and wrinkles. Nerve conduction may also be affected. Further, too much fat is sometimes removed from the wrong site, resulting in a misshaping of the surrounding tissue. Lastly, liposuction procedures are time consuming and tedious for both the surgeon and the patient.
As mentioned above, conventional liposuction treatment has been enhanced by the use of ultrasound. Following a surgical incision, a probe is inserted into a target area of adipose tissue in a patient. Ultrasonic waves, emanating from a transducer, are transmitted to the adipose tissue via the probe, forming cavitation bubbles and resulting in the liquefaction of that tissue. A transducer which converts electrical energy into mechanical vibrations may be located external to, or be incorporated into, the probe. The liquefied adipose tissue is then aspirated through a suction tube. While this procedure represents a clear improvement over standard liposuction, it still requires a surgical incision, which results in scarring of the skin surface, and significant recovery time for the patient of about 3-6 weeks.